Update Document to check the /XYZ len

[tamdao]

The issue arises because some PDFs return /XYZ coordinates in the format /XYZ x y instead of /XYZ x y z. This discrepancy causes the code to fail when attempting to unpack three values from an array that only contains two.

[github-actions]

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[tamdao]

I have read the CLA Document and I hereby sign the CLA

[JorjMcKie]

Thank you for spotting this!